Water: structure and properties
Hydrogen · Chemistry
Study notes
Why does ice float, and why does that matter for life? Step 1: In ice, H-bonds lock molecules into an open hexagonal lattice with empty space. Step 2: Open structure → ice less dense (0.917 g/cm³) than liquid water (1.0). Step 3: Ice floats, insulating the water below from freezing air. Step 4: Lakes freeze top-down; fish survive winter underneath. If ice sank, oceans would freeze solid!